1. Technical Field
The present invention generally relates to a bridge circuit and a short-circuit protection thereof and, more particularly, to a bridge circuit with short-circuit protection and a short-circuit protection method thereof.
2. Description of Related Art
With reference to FIG. 1A, in the inverter having a bridge inverter unit, short-circuit protection for the switches K1˜K12 on the same bridge arm is a key issue. Each of the bridge arms is provided with a current sensor. However, for an inverter with six bridge arms, as shown in FIG. 1A, six current sensors T1˜T6 are required to detect the current through each of the switches K1˜K12 on the bridge arms. As a result, the manufacturing cost and the circuit area are increased and the complexity in circuit design is enhanced as well.
A simplified method is to use a current transducer on the direct-current (DC) bus to detect the total current on a bridge circuit to be coupled thereto, as shown in FIG. 1B. In this configuration, if the current transducer is implanted by a current transformer, high-frequency voltage fluctuations across the bridge arm will occur due to the parasitic inductance of the current transformer. The current transformer has an inherited reset issue. Otherwise, the cost may increase if the current transducer is implemented by a Hall sensor.